Mass, Volume and Density Let me say it nowif you dont put the labels on your answers It Will
Be WRONG!!!!! Mass: A measurement of the amount of matter in an object It can be measured with a triple beam balance It is measured in
grams. Volume: Is the amount of object takes up. space
an There are several ways to calculate volume. We are going to look at the ruler method and the water displacement method. Using a Ruler
Just a quick reminderwe only measure in the metric system in this class!!! So how do we find the volume of an object using a ruler? If you said Length X Width X Heightyou
are ahead of the curve! Height Width Length L x W x H. ( We use this method when the object has a regular shape.)
Height Width Length So our formula looks like this: LxWxH Length = 4
W 3 idt h = Height = 2
What is our answer? If you said only 24 you would be wrongwhy? Length = 4 W
3 idt h = Height = 2 So what is the label we use?
Length = 4 W 3 idt h =
Height = 2 Centimeters cubed = written like this cm 3 What is going to happen?
Water Displacement So what is water displacement? Water Displacement How does it work?
Water Displacement Just like when you got into the tub, the water level had to go up in proportion to the amount of space you were taking up.
What type of objects are you going to use water displacement on? Water Displacement Place a known amount of water into the graduated cylinder How much water is in
this graduated cylinder? Water Displacement Very carefully place your object into the graduated cylinderwhat are some things you need to be aware of as you place the object into the graduated cylinder?
Water Displacement After placing the object carefully in the graduated cylinder, what should you do now? Water Displacement
Read the volume of the water after the object has been put in, then Water Displacement subtract your beginning water level from you ending water level.
26 mL 20 mL 6 mL Ending Water Level -Beginning Water Level Volume of the object Water Displacement
Now what is the unit of measurement we will be using with our answer. mL What is the
volume of this object? 3 mL Just to reviewif you have a regular uniformly shaped object that has a measureable length, height and width, we use which method of calculating volume?
If the object is irregularly shaped, then we use what method to calculate volume? Now comes the fun partwe have covered how to mass an object, how to calculate volume so we are ready to move on to calculating
Density Density is the relationship of mass to volume. Density is the amount of
matter that is packed into a specific space. It is determined by using the formula mass divided by volume (M/V = D) Now lets practice a problem Density =
20 g 10 cm 3 What is the density? 2g 3 cm
Lets do some practice problems: 75 mL of water was measured. An object was carefully dropped into the graduated cylinder. The water level rose to 90 mL. What is the volume of the rock? 15 mL
Lets do some practice problems: If the mass of an object is 30 grams and the volume of the 15 mL, what is the density? Density = 2 g mL Lets do some practice problems:
If the measurements of a metal bar are 10 cm, 5 cm and 2 cm, what is the volume of the metal bar? Volume = 100 cm 3
Lets do some practice problems: If the mass of the metal bar is 250 g and the volume is 100 cm3, what is the density? Density = 2.5 g 3 cm
GREAT JOB Now you know mass, volume, and density. Way to go scientists!